Fuel additive compositions are used in combination with a fuel, and they are generally intended for use with a specific type of fuel (e.g., petroleum distillate fuel such as gasoline, diesel, jet fuel, or other heavier fuel oil, but not generally multiple types of fuels across a broad range of the petroleum distillate spectrum in component molecular weight and/or classes of hydrocarbons such as alkanes, cycloalkanes, and aromatic hydrocarbons). The fuel additive composition, when mixed with the fuel, can result in the fuel have one or more improved combustion properties such as improved combustion efficiency, improved combustion energy/calorie content, reduced sulfur generation, reduced ash generation, etc.